Studies in Surface Science and Catalysis Advisory Editors: B. Delmon and J.T. Yates Vol. 36 METHANE CONVERSION Proceedings of a Symposium on the Production of Fuels and Chemicals from Natural Gas, Auckland, April 27-30, 1987 Editors D.M. Bibby DSlR Chemistry Division, Private Bag, Petone, New Zealand C.D. Chang Mobil Research and Development Corporation, Central Research Laboratory, P. 0. Box 1025, Princeton, NJ 08540, U.S.A . R.F. Howe Chemistry Department, University of Auckland, Private Bag, Auckland, New Zealand and S. Yurchak Mobil Research and Development Corporation, Paulsboro Research Laboratory, Paulsboro, NJ 08066, U.S.A . - - - ELSEVl ER Amsterdam Oxford New York Tokyo 1988 ELSEVIER SCIENCE PUBLISHERS B.V. Sara Burgerhartstraat 25 P.O. Box 2 1 1, 1000 AE Amsterdam, The Netherlands Distributors for the United Stares and Canada: ELSEVIER SCIENCE PUBLISHING COMPANY INC. 52, Vanderbilt Avenue New York, NY 10017, USA. LIBRARY OF CONGRESS Library of Congress Cataloging-in-Publication Data Methane conversion proceedings of a symposium on the production of fuels and chemicals from naturai gas. Auckland, April 27-30. 1987 editors. D.M. Bibby ... [et ai.1. p. cm. -- (Studies in surface science and catalysis . 36) InCludeS index. ISBN 0-444-42935-2 (U.S.) fl 300.00 cest.) 1. Synthetic fuels--Congresses. 2. Gas. Natural--Congresses I. Bibby. C. M. (David M.) 11. International Symposiufr on Methane Conversion (1987 Univepsity of Aucklano) 111. Series. TP360.M47 1988 665.7 3--dC19 87-34762 CIP ISBN 0-444-42935-2 (Vol. 36) ISBN 0-444-4 180 1-6 (Series) 0 Elsevier Science Publishers B.V., 1988 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the publisher, Elsevier Science Publishers B.V./ Science &Technology Division, P.O. Box 330, 1000 AH Amsterdam, The Netherlands. Special regulations for readers in the USA -This publication has been registered with the Copyright Clearance Center Inc. (CCC), Salem, Massachusetts. Information can be obtained from the CCC about conditions under which photocopies of parts of this publication may be made in the USA. All other copyright questions, including photocopying outside of the USA, should be referred to the copyright owner, Elsevier Science Publishers B.V., unless otherwise specified. No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any meth- ods, products, instructions or ideas contained in the material herein. Printed in The Netherlands XI F0REkD)RD It is with pleasure that we present the Proceedings of the International Symposium on Methane Conversion which took place in New Zealand from 27-30 April, 1987. The Symposium marked the successful inauguration in October 1985 of the world's first comnercial plant for production of gasoline from natural gas, based on the Mobil methanol-to-gasoline process. The plant is operated by the New Zealand Synthetic Fuels Corporation, of which Mobil is a shareholder. The symposium was held at the University of Auckland and concluded with a tour of the synfuel gas-to-gasoline plant at Motunui, near New Plymouth. The objectives of the Symposium were to present both fundamntal research and engineering aspects of the development and comrcialization of gas-toqasoline processes. These included steam reforming, methanol synthesis and methanol-to-gasoline. Possible alternative processes e.g. MOGD, Fischer Tropsch synthesis of hydrocarbons, and the direct conversion of methane to higher hydrocarbons were also considered. More than 130 delegates from a wide range of disciplines attended and the Symposium was successful in prmting interchange of ideas between scientists developing processes in the laboratory and engineers responsible for comrcialization. The Symposium prcgrarnne consisted of a series of invited lectures from industrial, university and government speakers, contributed papers and two poster sessions. The call for contributed papers resulted in submission of 85 abstracts, a large proportion of which came from industrial laboratories. Follming the grouping of papers at the Symposium, we present them here in the following broad categories: - Inethane conversion via methanol - alternative routes to methane conversion - zeolites and other catalysts - comrcialization of the gas-tc-gasoline process The work presented at the poster sessions is included in this volume as short papers. The Editors have felt obliged to carry out editorial changes in papers where obvious typing errors or lack of clarity affected the understanding. W e apologise for not being able to obtain an authorisation in every case but this was because of lack of time. The alternative of not accepting these papers, or XI1 of delaying publication of these Proceedings further was not justified in view of the high quality and imnediacy of the work presented. The Editors would like to thank the Authors for the quality of their presentations, and for participating in this volume. The Editors also thank the Organizing Committee for willingly giving their time and expertise to the Symposium, the Chairman of Sessions and the referees for their numercus contributions. We thank George Dibley and his staff of the Auckland University Centre for Continuing Education for arranging the Symposium and associated extra-curricular activities, and Neil Milestone for assistance in the preparation of this volume. Finally, we thank Dame Catherine Tizard, Mayor of Auckland, for opening the Symposium and welcoming the delegates to New Zealand and the City of Auckland. DAVID M BIBBY CLARENCE D CHANG RUSSELL F HOWE SEFGEI WRCHAK XI11 ORGANIZING AND SCIENTIFIC COMMITTT K.G. Allum New Zealand Synthetic Fuels Corporation D.M. Bibby DSIR Chemistry Division C .D. Chang Mobil Research and Developnent Corporation R.P. Cooney University of Auckland R.F. Howe University of Auckland N.B. Milestone E I R Chemistry Division R. Nicol DSIR Industrial Processing Division C.G. Pope University of Otago S. Yurchak Mobil Research and Development Corporation FINANCIAL SUF'poRT This Symposium was wde possible by financial support sponsorship from the following organizations: American Chemical Society American Institute of Chemical Engineers Mobil Research and Development Corporation Mobil Oil New Zealand Mobil South, Inc. New Zealand Department of Scientific and Industrial Research, Chemistry Division New Zealand Institute of Chemistry New Zealand Synthetic Fuels Corporation, Ltd University of Auckland D.M. Bibby, C.D. Chang, R.F. Howe and S. Yurchak (Editors), Methane Conversion 1 1988 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands THE NEW ZEALAND GAS-TO-GASOLINE PROJECT C.J. MAIDEN Chairman, New Zealand Synthetic Fuels Corporation Ltd., New Zealand ABSTRACT The Synfuel gas-to-gasoline complex is sited within 180 hectares of land at Motunui, Taranaki. It is designed to convert 52-55 PJ per annum of natural gas into 570,000 tonnes (14,450 barrels per stream day) of high octane gasoline. The conversion of gas to gasoline (GTG) takes place in two stages: first gas to methanol (GTM) and second methanol to gasoline (MTG). The two stages are integrated into a single complex to achieve optimum efficiency in management and operation. The GTM plant employs the ICI low-pressure Methanol Process sub-licensed from Davy McKee, and incorporates two methanol trains each capable of producing 2200 tonnes per day of methanol. The MTG plant employs Mobills fixed bed catalytic process using the Mobil proprietary zeolite catalyst, ZSM-5. The process is very similar to conventional vapour phase catalytic petroleum refinery processes, such as hydro-treating and platinum reforming. The plant is owned and operated by New Zealand Synthetic Fuels Corporation Limited (Synfuel) with a shareholding of Government 75 percent and Mobil 25 percent. Mobil provides technical and management services to the company. The plant was mechanically complete by June 30, 1985, ahead of schedule and about 17 percent under the original budget of US$1475 million. Commissioning and startup proceeded satisfactorily with the first gasoline produced on October 17, 1985. The gasoline is within specification and 739,000 tonnes have been produced to the end of March 1987. INTRODUCTION With more than a year's successful operation of the world's first gas-to- gasoline (GTG) plant it is an appropriate time to review the history and development of the project. The New Zealand Synthetic Fuels Corporation Ltd (NZSFC) was incorporated in September 1980 with the objective of. designing, constructing and operating a plant to manufacture gasoline. The Company was to convert natural gas owned by the Crown into gasoline, via methanol as an intermediate product, for a processing fee. Gasoline produced from the plant was to be owned by the Crown and subsequently sold to the oil marketing companies for distribution to the consumer. The project has its origins in recommendations from Liquid Fuels Trust Board to Government in 1979. 2 THE LIQUID FUELS TRUST BOARD In 1973, prior to the first energy crisis, New Zealand imported virtually all its liquid fuel requirements in the form of oil or its products. At this time such imports represented about 60 percent of New Zealand's primary energy requirements and cost less than 5 percent of the country's export earnings. After the first oil shock the cost of liquid fuels jumped to between 20 and 30 percent of export earnings and thereby severely weakened the economy. The second oil shock in 1979 further weakened the economy and a high reliance on Iranian crudes led to the introduction of "carless days", a (temporary) attempt to reduce the amount of car usage. The Liquid Fuels Trust Board (LFTB) was formed just prior to the Iranian revolution with the aims of assessing ways of reducing the need for imported fuels for transport purposes in New Zealand. The second oil shock created immediate pressure on the Board to determine how the products of New Zealand's natural gas fields could be used as or converted into transport fuels. New Zealand's two largest gas fields are the Kapuni and Maui fields. The Kapuni field has estimated recoverable gas reserves of 419 petajoules (PJ) and i s on-shore in Taranaki; whereas the Maui field with estimated recoverable gas reserves of 5193 PJ is 33 km off the coast of Taranaki. A number of alternatives were examined by the LFTB including compressed natural gas (CNG), liquefied petroleum gas (LPG), methanol as a gasoline extender, pure methanol as a gasoline or diesel substitute and the production of synthetic fuels. This work resulted in the presentation of two reports to Government, in August and October 1979, containing recommendations on an initial strategy for transport fuels supply and gas utilisation in New Zealand. Two major projects were recommended: A synthetic gasoline project to produce 500-600,000 tonnes per annum of gasoline from methanol produced from natural gas using a process developed by the Mobil O i l Corporation; A "stand-alone" methanol project, using natural gas as a feedstock, with the majority of product dedicated to export as chemical grade methanol and the remainder for local use as a fuel or as a chemical. It was also recommended that the approved expansion of the Refinery at Marsden Point in northern New Zealand take account of future production of synthetic gasoline. The canbined use of synthetic gasoline, indigenous condensate from Kapuni and Mad, and CNG and LPG in vehicles, was predicted to make New Zealand about 3 50 percent self-sufficient in transport fuels in the middle 19801s, and thereby save several hundred million dollars annually in overseas funds. The LFTB's recommendation to use natural gas to produce gasoline using the Mobil process was made following a comprehensive analysis of alternative synthetic fuel technologies. To assist them in their studies during 1979 the LFTB contracted overseas consultants including Ralph M. Parsons, the Badger Company, Davy McKee and Lurgi. These consultants undertook investigations into the state of the art of methanol and synthetic fuel technology and carried out comparative studies between the Mobil methanol-to-gasoline (MTG) process and the Fischer-Tropsch synthetic fuel process as used by SASOL in South Africa. The LFTB concluded, on the basis of these studies, that the Mobil process provided a more economic and efficient method of producing synthetic fuel than did Fischer-Tropsch synthesis. The Board also concluded that it was not possible for New Zealand to reach 50 percent self-sufficiency in transport fuels by the middle 1980's without synthetic fuel. With only condensate, CNG and LPG a realistic cmparable goal would be about 25 percent self- . sufficiency THE MOBIL PROCESS The success of the unique Mobil process lies in the zeolite catalyst ZSM-5. This catalyst is the most efficient known for the conversion of methanol to hydrocarbons in the gasoline range. The process has its origins during the 1960's. Originally looking for a means of VrackingtV or breaking down components of crude oil Mobills scientists researched a range of chemical catalysts including aluminosilicates. This work resulted, in 1968, in the synthesis of the zeolite ZSM-5 which was found to convert methanol into water and a mixture of hydrocarbons. This hydrocarbon mixture is essentially the same as gasoline produced by the traditional refining of crude oil. Development studies on the MTG process have been conducted since the early 1970's. Using a fixed-bed process, catalyst ageing tests of over 200 days were carried out, optimum process conditions were defined, and the quality of the gasoline produced was determined. In response to a request from the New Zealand Government, Mobil Research and Development Corporation built a four barrels per day fixed-bed pilot plant to demonstrate the feasibility of the gas-to-gasoline process. This was a major scale-up of the laboratory work and the pilot plant performed precisely as predicted. Reports to the LFTB by Lurgi and Badger also indicated confidence that the process would scale successfully from the pilot plant to 4 commercial size. The ZSM-5 catalyst does not have only one use. Mobil has commercialised six processes using ZSM-5, five of which are licensed for use in 25 chemical and refinery plants around the world. These varied applications have given Mobil wide experience in directly scaling up laboratory-size units to large commercial plants. Commercial experience has also confirmed laboratory predictions of high stability and long life for the catalyst. PROJECT CONCEPTS The project concepts were developed under the terms of a 1980 Government/ Mobil Memorandum of Understanding. By this acjreement a Joint Executive Committee (JEC) was to prepare a report which would include a plan for the design, construction, and operation of a plant to manufacture gasoline, and an assessment of the viability of such a project. Mobil assumed responsibility for overall project management, subject to the direction of the JEC, and Bechtel Petroleum Inc. was employed as Project Services Contractor. The JEC Report, completed in July 1981, concluded that the venture was clearly technologically feasible and commercially attractive. The Government and Mobil elected to proceed and concluded the various contracts in February, 1982. It was agreed that the plant would be owned and operated by the New Zealand Synthetic Fuels Corporation Ltd (Synfuel) with a Government shareholding of 75 percent and a Mobil shareholding of 25 percent. Mobil contracted to provide technical and management services to the company. The company was to operate on a tolling basis, with the Crown supplying the natural gas to the plant for processing into gasoline for a tolling fee. Title to the hydrocarbons was to remain with the Crown, which would sell the gasoline to the New Zealand petrolem marketing companies. Synfuel gasoline was to be priced competitively with gasoline produced from the Refinery at Marsden Point. Under the terms of the Processing Agreement between NZSFC and the Crown, the tolling fee to be paid by the Crown, when the plant operated at design capacity, was to cover all of NZSFC's costs including tax and debt service. Also, at design capacity, the fee was to provide the shareholders with a tax paid discounted cash flow rate of return on qualifying capital at risk of 16 percent adjusted for inflation. DESIGN OF TM PLANT The Synfuel plant is sited within 180 hectares of land at Motunui, Taranaki 5 TARANAKI I WAITARA / MOTUNUI Fig. 1. Location of Synfuel Complex